Unit and process of making the same.



MPH. RICE. UNIT AND PROCESS OF MAKING THE SAME. APPLICATION FILED 0012.1, 1913.

1,093,947. Patented Apr. 21, 191 1 UNITED STATES PATENT OFFICE.

MERRIT H. RICE, OF NEW ROCHELLE, NEW

YORK, assronon 'I'O'NATIONAL ELECTRIC UTILITIES CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

UNIT, AND PROCESS OF MAKING THE SAME.

Specification of Letters Patent.

. Patented Apr. 21, 1914.

. Application filed October 1, 1913. Serial No. 792,724. 1

To all whom ma concern:

Be it known t at I, M'nnm'r H. RICE, a

- citizen of the United .States residing at New Rochelle, in the county Westchester and State of New York, have invented ,new and useful Improvements in Units and Processes of Making the Same, of which the compound heating units,

following is a specification.

This'invention relates to units for electric stoves, furnaces and the like, and it has for its object increasing the mechanical strength and the durability of that type of devices.

Ithas also for its object the production of a unit for use in electrical apparatus 111 which carbon maybe employed as a resistance element and be subjected. to the elevated temperatures necessary in the use of such apparatus. A r

Another object of the inventionis to roduce a successful heating unit or cartridge which may be used repeatedly and WhlOh is in such form that it may be readily and conveniently assembled with others to form the like. 7 0 I Further objects ofthe nvention Wlll hereinafter appear.

It is a desideratum is the m a) which the I present invention relates to produce an electric heating un1t having carbon as the resistance element because carbon IS the cheape'st and most successful form of resistance.

Carbon cannot be used as a:resistance element when it is exposed to the air without deterioration, as itburnsat the temperatures to which it issubjected in use, and it flakes off, as it is termed in. the art. In attempts to overcome this flaking off of the carbon and the burning of it, carbon in different forms has been incased in metallic tubes and has been covered with different forms of vitreous material; but these attempts have failed to produce a successful unit having carbon as the resistance element, because of the forms of the devices and the materials and processes employed. One form of such unsuccessful devices of which I am aware consists of acarbon rod incased in a metallic tube and having Portland cement or like material set therearound. Portland cement, being porous, air and moisture may permeate it.

The present invention comprises a resistance element, preferably of carbon, graphite, or similar material, located in a protective casing and insulated therefrom by fusible heat-conducting material, the ends of the carbon being suitably connected to terminals which project through ends of the containing casing for connection with the source of electricity.

The invention also comprises the process by which this invention is made, consisting in placing a resistance element, preferably in the form of a carbon rod coated with asbestos cement in a metallic or other suitable casing, fillingthe space with a fusible material, preferably in the form of powdered enamel and usually in the form of ,enamel which melts or fuses at a temperature higher than the temperature to which the resistance element is use, and fusing such material to the rod and in the casing. The fusing is preferably accomplished by means of the resistance element itself. After it has been located in the "casing and the enamel has been poured in and also after the ends of the-casing have been suitably sealed and't'he terminals for the carbon insulated from the ends, an electric current sufficient to fuse the enamel is passed through the resistance element. If the unit to be made is to be used in apparatuses Where a temperature of 750 F. is to be used, I. preferably employ a fusing material such as an enamel which melts at a temperature of about- 1200 course, the invention is not limited except in its specific application to the use of such material, since the ends of the casing effectually seal the same, and if, during use, the fusible material should be heated to its melting point, it cannot leak from the v casing.

\Vhile applicant does not wish to confine himself to any theory in regard to the reason of the successful operation of his improved unit, nevertheless, so far as he is aware, he believes that the temperature of the element causes a slight melting or softening of the fusible material and thus in effect compacts it and makes the equivalent of a liquid seal during use through which it is impossible for any air to pass.

he accompanying drawings show one form of. a specific embodiment .of a car- F., but, of.

to be subjected in v,

' t ridge lating material, preferably in the form of made in accordance with my invention and serve to illustrate the manner in which it is made.

Figure 1 is a front elevation; Fig. 2 is a similar view on an enlarged scale and partly in section; Fig. 3 is across-section along line 33 of Fig. 2 on-an enlarged .scale.

In the drawings, reference character 1 designates a metallic or other suitable protective casing into which the electric resistance element 2, here shown-in the form of a cylindrical carbon rod, is placed. The carbon rod is provided at either end with a terminal 3 having the socket portions 4 and extremities 5 projecting beyond the ends of the casing. One end 6 is sealed by'means of the threaded bushing 7, having the s uared nut-likeend 8for the application 0% a wrench, and also by some self-hardening cement 9. In order to prevent the carbon from burning when it is being heated, as hereinafter described, 't is first coated with asbestos and some form of cement, such, for instance, as the vitrex retort cement, now to be found upon the market.

This makes the asbestos adhere and form anair-tight covering before the carbon. is heated. 10 designates this coating of asbestos and cement or other material. The

fusible heat-conducting and electric insupowdered enamel, 11, is poured into the open end of the casing and such end is then sealed in the same manner as the other end. v The unit is then heatedto at least the fusing point of the particular insulating material used and preferably by .means of an electric current passing through the resistance element. Ofcourse, any form of heating means may be employed, but the specific means and method disclosed is the most practicable and convenient.- It is also a cheaper mode of fusing the material and for that reason adds value to the invention.

I do not claim broadly a resistance element of any form or specifically of carbon having vitreous material fused thereto, as

such devices are known although, with the exception of the one I have invented, are not successful. I do not claim a resistance element of carbon inclosed .in a casing and insulated therefrom by means of vitreous material broadly, such as Portland cement Y and the like, as such a form of device is known, although not successful. But I consider myself the first to producea successful unit or cartridge in which the resistance element is not only effectually protected from contact with air but in which the material for accomplishing, this purpose is fused to the element and is in turn protected and maintained in position by means of acasing or the like, and I therefore consider myself entitled to all substitutes and equivalents of the above within the scope of the following claims.

What I claim is 1. A unit for electric stoves and the like, comprising .a resistance element having an air-tight cementitious coating, and a high temperature-melting electric insulating material fusedto said coating.

2. A unit for electric stoves and the .like, comprising a resistance element having an air-tight covering of cementitious material, an electric insulating and heat conducting material fused to said coating, and a protective covering for said material.

3. A unit for electric stoves and the like, comprising a resistance element having a coating of cementitious material containing asbestos, a high tem erature-mel ting' electric insulating material fused to said coating, and-a protective covering for said ma terial.

4:. The process of making an electric heating unit, which comprises locating a resistance element in sufiicient fusible insulating material contained in a protective casing to fill said casing and heating the said material to fuse itto the element.

5. The process of making an electric heating unit, which comprises coating an ele-.

ment with an air-tight'cementitious covering, locating such element in fusible insulating material cont-ainedin a protective casing and heating the said material to fuse it to theelement.

6. The process of making an electric heating unit, which comprises locating a resistance unit in powdered fusible'insulating material contained in a protective casing, and heating said material to fuse it to the element.

7. The process of making an electric heat-- ing unit, which comprises locating a resistance element in .a protective casing away from the walls thereof, filling the space with fusible insulating and heat-conducting material and passing a current through the element to'cause the material to fuse thereto.

8. The process of making an electric heating unit, which comprises locating aresistance element in fusible.powder'ed insulating material contained in a protective casing and passing a current through said element to fuse the powdered material thereto.

9. The process of making an electric heating unit, which comprises locating a carbon rod in fusible insulating material containing a protective casing and passinga current through said carbon to fuse the material thereto.

10. The process of making an electric heating unit, which comprises locating a carbon rod in powdered enamel contained in a protective casing and passing a current through said rod to fuse the enamel thereto.

11. The process of making an electric heat;

assess? ing unit, which comprises locating a resistance element having terminals at either end in fusible insulating material contained in a protective casing, sealing the ends of said casing While allowing the said terminals to project therethrough, insulating the terminals from the casing and heating the material to fuseit to the element.

12. A unit for electric stoves and the like, comprising a metallic sleeve containing a resistance element and an insulation therefor, the said insulation comprising a fusible substance fused to the element and filling the space in said sleeve not occupied by said element.

13. A unit for electric stoves and the like, comprising a sleeve, a carbon rod of less diameter than said sleeve substantiallyaxially located therein, and a high temperaturemelting electric insulating material fused-to said rod and filling the space in said sleeve not occupied by said rod.

14. A unit for electric stoves and the like, comprising a metallic sleeve, a resistance element substantially axially located therein and having terminals-. attached thereto projecting beyond the ends of said sleeve, and enamel fused to said resistance element and filling the space in said sleeve not occupied by said resistance element.

In testimony whereof, I have hereunto set my hand this 29th day of September, 1913,-

in the presence of subscribing witnesses.

MERRIT H. RICE.

Witnesses:

E. O. VAN GLAHN, F REDERIGK N. BAYLISB 

